This disclosure relates to electrically conductive polymers, and methods of manufacture thereof, as well as articles comprising the polymers.
Electrically conductive polymer foams are of utility in a wide variety of applications, including as electrical contacting devices, in sensors, and in applications requiring electromagnetic interference (EMI)/radio frequency interference (RFI) shielding and/or electrostatic dissipation. Current materials capable of EMI/RFI shielding include, for example, beryllium-copper finger stock, metal foil or metallized fabric wrapped around non-conductive foam gaskets, non-conductive gaskets coated with conductive materials, and metal-containing fillers loaded into silicone resins. Other electrically conductive foams are also known, for example certain polyurethanes and polyolefins. One difficulty with currently available methods and materials is that the addition of the high levels of conductive filler(s) sufficient to achieve high conductivity affects the compressibility and processability of the polymer. In addition, use of such high filler levels increases the cost of the polymer blend. Users are often forced to make a trade-off between the cost and the quality of the material.
It would be a further advantage to provide polymer foams where the amount of added filler is minimized, while maintaining a suitable electrical conductivity. It would be a further advantage that the compressibility, processability, and other physical properties of the foam that are desired for a particular application not be significantly adversely affected.
There accordingly remains a need in the art for compositions and methods whereby foams can be provided with both electrical conductivity and compressibility and processability, particularly without significant adverse effect on one or more physical properties desired for a particular application.